   [asset]
   (let [stream (content asset)]
     (if stream
-      (-> (ring/response stream)
+      (->
+        (ring/response stream)
+        (ring/header "Expires" (@asset-configuration :expiration))
         (ring/content-type (get-content-type asset))))))
 
 (defn wrap-exception-handling

  [handler]
  ; Just a placeholder for now
  handler)

(defn initialize-assets
  "Initializes asset handling for Cascade. This sets an application version (a value incorporated into URLs, which

  (let [root (str "/" virtual-folder "/" application-version)]
    (reset! asset-configuration
      {:application-version application-version
       :expiration (now-plus-ten-years)
       :public-folder public-folder
       :virtual-folder virtual-folder
       :file-path (str root "/file/")
